Electrical switch



Jan. 3, 1950 1... J. KALWO 2,493,14

ELECTRICAL SWITCH Filed July 31, 1947 ATTORNEY Patented Jan. 3, 1950 LudwigJ. Kalwo, New York, N. Y., assignor to Trine Manufacturing iCorporation, New York,

N. Y., a corporation Application July 31, 1947, Serial No. 765,099

type.

It is the primary object of the present invention to provide a switch of the push button type which,

while made from a minimum number of simple and inexpensive parts, is nevertheless pleasing in appearance and reliable in operation.

, It is another object of the present invention to provide the switch with an exceptionally large operating button which can hardly be missed by an operator, and to construct the switch so that the contacts thereof will move into wedging engagement with one another and unfailingly close the circuit, even if the button is unevenly depressed.

It is another object of the present invention to provide the switch with contacts which will neither wear rapidly nor break easily, and which will have an exceptionally long useful life.

The above and other objects, features, and advantages of the invention will be fully understood from the following description considered in connection with the drawings.

In the drawings: I

Fig. 1 is a plan view of a switch embodying the present invention; I

accompanying illustrative :25

4Claims. (Cl.-200--159) Fig. 2 is a longitudinal section through the switch, taken on the line 2--2 of Fig. 1;

Fig. 2A is an enlarged sectional View of a part of Fig. 2;

Fig. 3 is a cross section through the switch,

taken substantially on the line 3-3 of Fig. 2;

Fig. 4 is a section taken on the line 4-4 of Fig.

3; and

Figs. 5 and 6 show, greatly enlarged, the movable contact member of the switch in different elevations.

Referring to the drawings, and more particularly to Figs. 1 to 3 thereof, the reference numeral l0 designates a switch which comprises a housing 12, a terminal board 14 carrying spaced contacts l6, and a push button l8 which carries a contact member 20. The switch housing 12, whichmay be stamped and formed from sheet metal, is open at the bottom for the insertion therein of the terminal board l4 and a base member 2!. The terminal board 14 is made of any suitable insulating material, and the base member 2| is preferably also made of insulating material. The terminal board l4 and base member 2! may be held in the switch housing l2 by means of bentover lugs 22 on the latter (Figs. 2 and 3). More particularly, the lugs 22 hold the terminal board 2 I4 and base member 2| in firm engagement with stamped funnel-shaped sockets 24 in the housing l2 that serve for the reception of the heads of screws (not shown) by means of which the switch is to be mounted on any suitable support, such as a wall, for instance. The terminal board l4 and base member are to this end provided with holes 26 which are in alignment with the sockets 24 for the reception of the shanks of the mounting screws.

The contacts l6 are preferably formed by strips of any suitable conductive material, such as copper, and are held on the board M by conductive eyelets 28 (Fig. 2) which are mounted in the board. The eyelets 28, which are in conductive engagement with the adjacent contacts I5, respectively, are internally threaded for the reception of terminal posts or screws 30 by means of which the wires in a circuit may be electricallyconnected with the contacts IS. The adjacent ends 32 of the contacts l6 project into a longitudinal slot 34 in the board l4 and are preferably inclined to each other in the fashion shown in Fig. 2 for a purpose which will appear obvious hereinafter. In order to lock the contacts I6 against turning movement on the board M, the former are provided with inwardly formed ends 38 which are anchored in the board M in the manner shown in Fig. 2.

The switch housing I2 is provided with a longitudinal slot 40 through which the push button l8 projects with slight clearance. The push button I 8 is normally urged by springs 42 into the projected position shown in Fig. 2, in which shoulders 43 on spaced, laterally projecting bosses 44 on the push button engage the top portion 46 of the switch housing l2 (Figs. 2 and 3). The push button I8 pivotally carries at 48 the movable. contact member 20, the latter being received in a depression 50 in the push button with such clearance as to permit slight pivotal movement of the contact member 20 relative to the push button.

The movable contact member 20 comprises spaced prongs 52 (see also Figs. 5 and 6) which are integral with, and depend from, a base 54. Also integral with, and depending from, the base 54 are side walls 56 which flank the prongs 52 and have inwardly bent lugs '58 that engage the adjacent prongs and prevent their further outward spread thereat. Thus the movable contact member 20 may readily be made in a single piece from conductivefsh'eet material which preferably has some resiliency, such as beryllium copper, for instance.

longitudinal extent by the operators hand. The

pivotal mounting of the movable contact member on the push button l8 will insure closure of the switch at the fixed contacts 16 by the bridg ing contact member 20, even if the push button I8 is depressed unevenly, as near either end thereof, for example. This is due to the tact that the prongs 52 of the pivoted contact member 20 will, on depression of the push button 18 anywhere along its longitudinal extent, invariably be guided into wedsires enga ement with h inclined ends 3-2 of the fixed contacts it, the depression 5.0 in the push but on preventin he contact 1member 20 irom ever swin in completely out of operati e alignment with the. fixes. contacts M5. 1115 :is app rent that the sw tch will close unfailin -1y even if h push b t er: 5.8 is depressed nevenly.-

fbe sp cific'censtr etion of he movable contact member 26, and particularly the provision of th l gs 58, mak s it possible tameension or sprin -lead the prongs so that t y nor-- mally en a e he ad acent lugs 53 with a yielding fier e. on dep essin h pus bu n 18 the prongs -52 will enga e the fixe contacts to with a yielding force which is far reate than the force that c uld be exer d by th se prongs if they were not preensioned- The gr t ad vantage of he pre-tensiened prongs 52 l es. not only in the firm contact between the latter and the fixed con acts which mak s f r nf iling cl sure of the switch every tim the push button is depressed, but lies also in the energe ic recovery after each switch opening. of the pretensioneel prongs to their normal relative d spositi n, i. e. into firm engagement wi h the lugs 58. Hence, the prongs 52 are not liable to be bent ou o their normal relative disposition even over a long period of use, thus lending to the instant switch an unusually long useful life. Also, the preensioned prongs .52 .of the movable cont ct mem er 20 come in o firmer wed ing enga e: men with the fixed contacts 16 than the would if they Were not ore-tension gl, wi h he resu t that the orange -52 nd fixed contacts 1.6 are eli eleaning to a greate xten than a hers? efore possible and, hence, inspire elec ri al con: tact over an exceedingly lons'period of time- While I have shown and described the preferred embodimen of my invention i will be nders o d that various changes may be made he present nvention wi hout depa t ng from the underlying idea or principles of the inyen-v tion With n th scope of the appended cl msl-Iay ng thus escr ed my n ntion, what .1 laim an esire o secur by L tters Patent is;

1. In a swit h having a h usin and spaced fix d conta ts well as a depre sible pu h bilt on, a member arr e by said push-bu ton and having condn tively c nne ted, spaced projecting prongs entering with their ends between said fixed contacts and wedging against the latter, respectively, on depression of said pushbutton, and stops carried by said member wholly externally of the space between said prongs and straddling the latter intermediate their lengths at a distance from said ends thereof, said prongs tensioned normally to engage said stops, respectively, with a yielding force, and said prong ends being outwardly flexible beyond the limits normall imposed upon them by said stops.

.2. A contact member for a switch, comprising a base, integral prongs projecting in the same direction from opposite sides, respectively, of said base and stops carried by said base wholly externally of the space between said prongs and sl mming the mter intermediate their lengths at a distance from their free ends, said prongs being tensioned normally to engage said stops,

respectively, with a yielding force, and said prong ends being outwardly flexible beyond the limits normally imposed upon them by said stops.

3. A one-piece contact member for a switch, comprising a base portion, prong portions integral with and projecting in the same direction from opposite sides, respectively, of said base portion, and stop portions integral with said base portion and straddling said prong portions intermediate their lengths at a distance from their free ends, said prong portions being tensioned normally to engage said s'top portions, respectively, with a yielding iorce, and said ends of the prong portions being outwardly flexible beyond the limits normall imposed on them by said stop portions.

4. A contact member for a switch, comprising a base, integral prongs projecting in the same direction from opposite sides, respectively, of

said base, and integral side walls projecting in said same direction from said base on opposite sides, respectively, of said prongs, each of said side walls having lateral lugs straddling the adjacent side margins of said prongs intermediate their lengths at a distance from their free ends,

said prongs being tensioned normally to engage the adjacent lugs, respectively, with a yielding and said prong ends being outwardly flexible beyond the limits imposed upon them by said lugs.

LUDWIG J. KALWO.

REFERENCES CITED he follow ng r ferences are of ecord in the Great Britain Sept. 7, 1922 

